include/linux/hw_random.h

0001 /*
0002     Hardware Random Number Generator
0003
0004     Please read Documentation/admin-guide/hw_random.rst for details on use.
0005
0006     ----------------------------------------------------------
0007     This software may be used and distributed according to the terms
0008         of the GNU General Public License, incorporated herein by reference.
0009
0010  */
0011
0012 #ifndef LINUX_HWRANDOM_H_
0013 #define LINUX_HWRANDOM_H_
0014
0015 #include <linux/completion.h>
0016 #include <linux/types.h>
0017 #include <linux/list.h>
0018 #include <linux/kref.h>
0019
0020 /**
0021  * struct hwrng - Hardware Random Number Generator driver
0022  * @name:       Unique RNG name.
0023  * @init:       Initialization callback (can be NULL).
0024  * @cleanup:        Cleanup callback (can be NULL).
0025  * @data_present:   Callback to determine if data is available
0026  *          on the RNG. If NULL, it is assumed that
0027  *          there is always data available.  *OBSOLETE*
0028  * @data_read:      Read data from the RNG device.
0029  *          Returns the number of lower random bytes in "data".
0030  *          Must not be NULL.    *OBSOLETE*
0031  * @read:       New API. drivers can fill up to max bytes of data
0032  *          into the buffer. The buffer is aligned for any type
0033  *          and max is a multiple of 4 and >= 32 bytes.
0034  * @priv:       Private data, for use by the RNG driver.
0035  * @quality:        Estimation of true entropy in RNG's bitstream
0036  *          (in bits of entropy per 1024 bits of input;
0037  *          valid values: 1 to 1024, or 0 for unknown).
0038  */
0039 struct hwrng {
0040     const char *name;
0041     int (*init)(struct hwrng *rng);
0042     void (*cleanup)(struct hwrng *rng);
0043     int (*data_present)(struct hwrng *rng, int wait);
0044     int (*data_read)(struct hwrng *rng, u32 *data);
0045     int (*read)(struct hwrng *rng, void *data, size_t max, bool wait);
0046     unsigned long priv;
0047     unsigned short quality;
0048
0049     /* internal. */
0050     struct list_head list;
0051     struct kref ref;
0052     struct completion cleanup_done;
0053 };
0054
0055 struct device;
0056
0057 /** Register a new Hardware Random Number Generator driver. */
0058 extern int hwrng_register(struct hwrng *rng);
0059 extern int devm_hwrng_register(struct device *dev, struct hwrng *rng);
0060 /** Unregister a Hardware Random Number Generator driver. */
0061 extern void hwrng_unregister(struct hwrng *rng);
0062 extern void devm_hwrng_unregister(struct device *dve, struct hwrng *rng);
0063
0064 #endif /* LINUX_HWRANDOM_H_ */